MRI-guided therapy procedures have the potential to reduce the invasiveness of surgical approaches. The use of intraoperative MRI can also result in the discovery of novel interventional surgical applications. The long-term objective of this Program Project has been to provide the scientific medical and technical infrastructure for the development of intraoperative MRI. The work proposed involves an integrated, coordinated, multi-disciplinary translational research effort in developing MRI-guided procedures which can be tested in future clinical trials. The proposal addresses critical areas of intraoperative MRI which may have significant impact on the future of this emerging field. These specific areas are: MRI-guided neurosurgery; MRI-guided, ultrasound surgery; image processing technologies and display tools for surgical for surgical guidance; and dynamic, adaptive volumetric image acquisition techniques. Project 1 aims to develop an integrated system of pre- and intra-operative image acquisition, online image processing and intraoperative display which allows the utilization of all the accessible intraoperative and preoperative information for image-guided neurosurgery. The objective of Project 2 is to implement MRI guided and and monitored focused ultrasound surgery used in combination with radiation therapy for the effective treatment of small malignant breast tumors. In Project 3 we continue to develop and implement high performance computer integration of pre-operative MR data with intraoperative images in order to guide surgery intraoperatively . The proposed research in Project 4 is to develop, implement and improve fast 3D dynamic adaptive MRI techniques to meet the specific needs of several interventional MR applications. This Program Project emphasizes the interaction of closely related individual research projects. The individual components are not only well integrated but there is also significant cross-fertilization and active interchange between them. We present a plant for the integrated development of therapeutic techniques which are optimized through MRI-guidance, monitoring and control. We have been providing a rapid transfer of new developments from the laboratory to clinical applications. With this translational research we refine and validate the experimental methods and techniques development and implemented previously.